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Method for recycling acid and valuable metal from oxalic acid wastewater

A technology for recovering valuable metals and acids, applied in the separation/purification of carboxylic acid compounds, chemical instruments and methods, organic chemistry, etc., can solve the problems of failure to fully utilize resources, environmental pollution, etc., and achieve automatic control, Realize the effect of zero emission and low production cost

Inactive Publication Date: 2009-08-12
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These methods can realize the recovery and utilization of oxalic acid in wastewater, but for the valuable metals and inorganic acids in wastewater, they still use alkali to neutralize the discharge, which fails to realize the full utilization of resources and also leads to serious environmental pollution.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Get 1000ml oxalic acid wastewater, its composition is: oxalic acid content 30g / l, hydrochloric acid content 2.0mol / l, metal Co 2+ The concentration is 1.0g / L.

[0022] (1) Extraction and recovery of oxalic acid:

[0023] (1) acidic oxalic acid waste water is precisely filtered to obtain clarified liquid;

[0024] (2) Extract oxalic acid from the clarified liquid with dimethylheptyl methylphosphonate+sulfonated kerosene (volume ratio is 1: 1), the extraction mixing time is 5 minutes, and the volume ratio of the organic phase to the aqueous phase is 0.5, The number of stages is 5;

[0025] (3) washing the organic phase loaded with oxalic acid with deionized water, the volume ratio of the organic phase to the deionized water is 6, and the number of stages is 2;

[0026] (4) Back-extract oxalic acid from the washed organic phase with deionized water, the volume ratio of the organic phase to the deionized water is 0.8, and the number of stages is 10;

[0027] (5) Concent...

Embodiment 2

[0035] Get 1000ml oxalic acid wastewater, its composition is: oxalic acid content 25g / l, hydrochloric acid content 3.0mol / l, metal Co 2+ The concentration is 1.0g / L.

[0036] (1) Extraction and recovery of oxalic acid:

[0037] (1) acidic oxalic acid waste water is precisely filtered to obtain clarified liquid;

[0038] (2) Extract oxalic acid from the clarified liquid with dimethylheptyl methylphosphonate+sulfonated kerosene (volume ratio is 1: 2), the extraction mixing time is 5 minutes, and the volume ratio of the organic phase to the aqueous phase is 0.8, The number of stages is 6;

[0039] (3) washing the organic phase loaded with oxalic acid with deionized water, the volume ratio of the organic phase to the deionized water is 8, and the number of stages is 3;

[0040] (4) Back-extract oxalic acid from the washed organic phase with deionized water, the volume ratio of the organic phase to the deionized water is 1.0, and the number of stages is 10;

[0041] (5) Concent...

Embodiment 3

[0049] Get 1000ml oxalic acid wastewater, its composition is: oxalic acid content 30g / l, hydrochloric acid content 3.0mol / l, metal Co 2+ The concentration is 1.0g / L.

[0050] (1) Extraction and recovery of oxalic acid:

[0051] (1) acidic oxalic acid waste water is precisely filtered to obtain clarified liquid;

[0052] (2) Extract oxalic acid from the clarified liquid with dimethylheptyl methylphosphonate+sulfonated kerosene (volume ratio is 1: 3), the extraction mixing time is 5 minutes, and the volume ratio of the organic phase to the aqueous phase is 1.0, The number of stages is 5;

[0053] (3) washing the organic phase loaded with oxalic acid with deionized water, the volume ratio of the organic phase to the deionized water is 10, and the number of stages is 2;

[0054] (4) back-extract oxalic acid from the washed organic phase with deionized water, the volume ratio of the organic phase to the deionized water is 1.0, and the number of stages is 12;

[0055] (5) Concen...

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Abstract

The invention discloses a method for comprehensively recovering acid and valuable metals from waste water of oxalic acid, comprising the steps: neutral phosphorus type extracting agent is used for extracting the oxalic acid, and then de-ionized water is used for back extracting the oxalic acid from the washed organic phase; the obtained diluted oxalic acid solution is concentrated and crystallized to obtain oxalic acid crystal; after the oxalic acid is extracted, acid solution is adjusted by chloride or chlorine hydride solution to ensure the concentration of chloridion to be not less than 3.0mol / L; valuable metallic ions are extracted out of the acid solution with the adjusted concentration of chloridion by polymer amine extracting agent, and the valuable metals is back extracted out from the washed organic phase by using dilute hydrochloric acid or dilute sulphuric acid solution. The method leads the recovery rate of the oxalic acid in the waste water of oxalic acid to be more than 95%, the recovery rate of valuable metals be more than 95%, the oxalic acid content of the recovered oxalic acid crystal to be more than 99.5%, the oxalic acid content of the inorganic acid to be less than 0.2g / L and the concentration of the valuable metallic ion to be less than 0.05g / L. The method can realize the comprehensive recycling of various valuable materials in the waste water and zero emission of waste water.

Description

technical field [0001] The invention relates to a method for comprehensively recovering oxalic acid, inorganic acid and valuable metals from oxalic acid wastewater. Background technique [0002] Oxalic acid is widely used in the production of metal oxalate in metallurgy, chemical industry and other industries. In the process of using oxalic acid to precipitate metal, a large amount of acidic wastewater is often produced. This wastewater generally contains unreacted oxalic acid, other inorganic acids generated by the reaction and unreacted reacted metal ions. The conventional treatment method of oxalic acid wastewater in the prior art is to use alkali to neutralize to neutral-filter-filtrate direct discharge process. It needs to consume a large amount of alkali, and wastes a large amount of free inorganic acids and valuable metals in waste water, and causes serious pollution to the environment; there is also a method that uses lead sulfate as an intermediate for recovery. Th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C55/06C07C51/48C22B3/38C22B3/28C01B7/07C02F1/58C02F9/02C02F1/26
CPCY02P10/20
Inventor 田庆华郭学益李治海易宇
Owner CENT SOUTH UNIV
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